Mobile communication systems are under constant development. New services are being introduced and the capacity which may be offered to users is increasing. Basic factors that need to be taken care of in the development of the present and future systems are quality of service offered to users and the available communication resources.
The quality of service (QoS) is measured using given parameters which may be system dependent. Usually a given QoS target is set for each connection. The quality of a communication link should fulfil the target criterion but not exceed it needlessly. In some systems, adaptive modulation and coding (AMC) is utilized to select the most appropriate modulation order and coding rate to be used on a connection at a given time on the radio link so that the target criterion is achieved and communication resources are used efficiently.